where are xenarthran found

What is Xenarthra?

Xenarthra is the animal group which includes the sloths, armadillos and anteaters. The xenarthrans originated in South America around 59 million years ago. Although at one time xenarthrans were found throughout the Americas, today only one xenarthran, the nine-banded armadillo, is found as far north as the United States.

What are extinct xenarthrans?

Extinct xenarthrans include the glyptodonts, pampatheres and ground sloths. Xenarthrans originated in South America during the Paleocene about 59 million years ago. They evolved and diversified extensively in South America during the continent's long period of isolation in the early to mid Cenozoic Era.

What do all xenarthrans have in common?

Because of their shared ancestry, all xenarthrans have certain things in common. The name Xenarthra, as we’ve found, refers to the animals’ uniquely jointed spines. We’ve also found that all xenarthrans are placental mammals. But there are several other xenarthran characteristics.

Is Xenarthra extinct?

Extinct xenarthrans include the glyptodonts, pampatheres and ground sloths. Xenarthrans originated in South America during the late Paleocene about 60million years ago. They evolved and diversified extensively in South America during the continent's long period of isolation in the early to mid Cenozoic Era.

When did the Xenarthra live?

Xenarthrans are known only from the Western Hemisphere and arose in South America during the Paleocene Epoch (65.5 million to 55.8 million years ago).

Are armadillos related to sloths?

Sloths are xenarthrans – their closest relatives include anteaters and armadillos. And, among other things, large, curved claws and powerful forelimbs for digging are common xenarthran traits. It's likely that the last common ancestor of two- and three-toed sloths shared these features, too.

Is an aardvark a Xenarthra?

It used to be that Xenarthra was the perfect clade—well, almost. Armadillos and sloths and anteaters and pangolins and even aardvarks used to be in the same order—not called Xenarthra, but Edentata, a term attributed to Félix Vicq d'Azyr and Georges Cuvier, both leading French biologists in the late eighteenth century.

Is sloth toothless?

The order was previously called the Edentata, which means “without teeth.” However, sloths are not actually toothless. They have molars, or chewing teeth, that have no roots and continue to grow throughout their lives.

What is the meaning of Xenarthra?

Definition of Xenarthra : a suborder or other division of Edentata comprising the American anteaters, armadillos, sloths, and usually the extinct ground sloths.

Do armadillos lay eggs?

How many eggs do armadillos lay? Armadillos do not lay eggs. A female armadillo gives birth to live babies, which are called 'pups' after a gestation period of three to five months, which can extend up to a period of eight to nine months due to something called delayed implantation.

What is the predator of a sloth?

Jaguars and eagles are common predators of sloths.

Do armadillos have teeth?

Armadillos have numerous teeth: 14-18 per jaw. The jaws of species of Dasypus do not open wide and they catch their food with their tongues like anteaters do. 3. Slender snouted skull of a long-nosed, nine-banded armadillo, Dasypus novemcinctus, with many small peg-like cheek teeth.

Do armadillos eat ants?

Armadillos, it turns out, eat fire ants. They feast on the developing eggs laid by the queen, and probably do cut into infestations, according to Larry Gilbert, the Brackenridge Field Laboratory director at the University of Texas, in a website post.

Are sloths related to elephants?

According to the results, the three-toed sloth is more closely related to a large family that included ancient elephant-sized ground sloths; meanwhile, the two-toed sloth appears to be the last survivor of an ancient lineage previously thought extinct.

Are armadillos and pigs related?

This isn't true. Armadillos are only closely related to other xenarthrans — South American anteaters and sloths. This group is unique to North and South America, and is not closely related to any other group of mammals. The mammal that is most often confused with an armadillo is the pangolin (Order Pholidota).

Where did the Xenarthrans come from?

Xenarthrans are known only from the Western Hemisphere and arose in South America during the Paleocene Epoch (65.5 million to 55.8 million years ago). The fossil record shows that the group was both more diverse and more widely distributed as recently as the Pleistocene Epoch (2,600,000 to 11,700 years ago), when ground sloths colonized the islands of the Greater Antilles and glyptodonts, ground sloths such as Megatherium, and giant armadillos roamed North America. At least one species of ground sloth reached present-day Alaska.

What is the name of the vertebrae that are xenarthrous?

The namesake feature shared by all members of Xenarthra is seen in the lower backbone. The lumbar vertebrae are “xenarthrous”; that is, they have extra contacts (joints, or arthroses) that function to strengthen the lower back and hips.

What is the name of the ancient lineage of mammals?

See Article History. Alternative Title: Xenarthra. Xenarthran , (magnorder Xenarthra), an ancient lineage of mammals comprising the armadillos (order Cingulata) and the sloths and anteaters (order Pilosa). The namesake feature shared by all members of Xenarthra is seen in the lower backbone. The lumbar vertebrae are “xenarthrous”;

Where do sloths live?

All five living species are limited to the lowland tropical forests of South and Central America, where they can be found high in the forest canopy sunning, resting, or feeding on leaves.

Do xenarthrans eat armadils?

As a result, xenarthrans eat less than other mammals and have body temperatures that are a few degrees cooler. Present distribution of xenarthrans is restricted to Latin America, the exception being the nine-banded armadillo ( Dasypus novemcinctus ), whose range extends into the southern United States.

Where did the Xenarthra originate?

Xenarthra is the animal group which includes the sloths, armadillos and anteaters. The xenarthrans originated in South America around 59 million years ago. Although at one time xenarthrans were found throughout the Americas, today only one xenarthran, the nine-banded armadillo, is found as far north as the United States.

What is the Xenarthra?

Xenarthra is the group of mammals that contains the sloths, anteaters and armadillos. Xenarthra is a ‘superorder’ – a group of related animals that contains other, smaller groups of even more closely-related animals. A superorder is itself a subset of a larger group of animals. The superorder Xenarthra is part of the class Mammalia, ...

What is the evolution of Xenarthra?

Xenarthra Evolution. Xenarthrans are placental mammals. Placental mammals give birth to relatively well-developed young, who were nourished by an organ known as a placenta while developing in their mother’s womb. This separates them from the egg-laying monotremes, and the pouched marsupials.

What are the two orders of Xenarthra?

The superorder Xenarthra contains two orders: Cingulata and Pilosa. The order Cingulata contains today’s armadillos and their extinct relatives. The order Pilosa is divided into two suborders: Folivora, which includes the sloths and their extinct relatives; and Vermilingua, which contains today’s anteaters.

What are the characteristics of Xenarthra?

Xenarthra Characteristics. On the surface a hairy, tree-dwelling sloth doesn’t seem to have much in common with an armored, burrowing armadillo. If you go far enough back in each of their family trees, however, you’ll arrive at the same place; an animal from which all today’s xenarthrans are descended.

When did Xenarthrans first appear?

You can find out more about the different types of mammal here: Types of Mammal. Xenarthrans first appeared around 59 million years ago , during the Paleocene. (The Paleocene is the first epoch of the Paleogene Period.) They originated in South America.

What are the four species of anteaters?

Anteaters. Northern tamandua – one of four living species of anteater. Four species of anteater are alive today: the giant anteater, silky anteater, northern tamandua and southern tamandua. The giant anteater, which as its name suggests is the largest species, is the only purely terrestrial (ground-dwelling) anteater.

Where did the Xenarthrans originate?

Paleontological records suggest that all xenarthrans originated in South America, and the distributions of all current and extinct species have been confined to specific regions of the Americas, primarily South America.

What is the Xenarthra?

Current molecular evidence indicates that the Xenarthra represent one of the four major clades of placental mammals. There are two distinct groups OF Xenarthra: (1) The Cingulata, which include all modern-day armadillos (families Dasypodidae and Chlamyphoridae).

What has rocked the stability of Xenarthran taxonomy?

The advent of new morphometric and, in particular, molecular techniques has rocked the stability of xenarthran taxonomy, resulting in important changes – a process that has only just begun and will certainly lead to additional taxonomic changes in the near future.

Where do sloths live?

2.2 Folivora (= Tardigrada or Phyllophaga), or sloths (families Bradypodidae and Megalonychidae): modern sloths live almost exclusively in trees, while the large, prehistoric forms were terrestrial. Sloths are famous for their slow movements and uncanny ability to hide in the tree canopy.

What is the Xenarthra?

Xenarthra is one of the basal placental superclades. Xenarthra is approximately 100 million years old and includes armadillos, anteaters, and sloths. Xenarthrans share unique features including supplementary intervertebral articulations, internal testes, and low metabolic rates. Xenarthran neocortex shares a common organizational plan with all other mammals, but in some species, the somatomotor arrangement is unique, possibly representing an evolutionary intermediate between marsupials (eg, opossums) and Boreoeutheria (eg, felines, primates). The cortical laminae of xenarthrans are not as defined as in other clades. In all xenarthrans examined, striking modular features in layer II of cortex occupy a great extent of neocortex.

What order are Xenarthrans in?

Xenarthrans were previously classified in an order termed Edentata, found to be polyphyletic and that also included ant-eating Pangolins. With the reclassification of the latter to the Pholidota order, the orders Cingulata (armadillos) and Pilosa (anteaters and sloths) were classified together in the superorder Xenarthra (odd joints). Xenarthra display fascinating biological peculiarities such as fused pelvic bones, spine reinforcing bones, and a peculiar blood vessel structure that allows energy sparing by an extremely low metabolic rate. These adaptations did not prevent a massive extinction of a huge number of representatives of this taxon so that the current extant genera represent only a minor part of those found in the Tertiary. In modern times the specific niche destruction due to human action certainly contributed, but the overall causes of this massive extinction are still under debate.

What are the characteristics of a xenarthra?

The Xenarthra bear several unique anatomic traits such as additional (xenarthrous) joints of lumbar vertebrae; fusion of the ischium to the anterior caudal vertebrae; a secondary scapular spine; extensive retia mirabile in the limbs; paired postrenal venae cavae; and ossified sternal ribs. Their well-developed claws are used for digging, clinging to tree branches, and defense. Except for the toothless Vermilingua, xenarthrans have significantly reduced, homodont, continuously growing teeth that lack enamel. Caniniform teeth are present in sloths. The most conspicuous morphologic feature of armadillos is the presence of a carapace consisting of ossified dermal tissue covered by epidermal scales.22 Sloths have specialized, large stomachs consisting of several chambers, in which bacterial flora breaks down and ferments rough plant material. They descend to the ground about once a week to defecate.

What is a xenarthran?

Together, the living families and extinct families constitute the Xenarthra. Xenarthrans are a small group of insectivores and herbivores of small to medium body size (up to around 60 kg). In the past however, xenarthrans were much more diverse and numerous.

How many species of armadillos are there in the Edentata?

Members of the mammalian group Edentata not only include the 31 living species of armadillos, true anteaters, and tree sloths, but also contain eight families of extinct ground sloths and armadillo-like animals. Together, the living families and extinct families constitute the Xenarthra.